The "key" word in a WHY question -

Consider any why-question - 

Say,

Why does a chilly taste spicy? or

Why is this school named Arthur C. Clarke centre?

Now consider the first one - 

Why does a chilly taste spicy?

Now, this is a "higher-order" derived question, which rests on some other question. (In fact, as we will see, questions). 

Which is, firstly, how does a chilly taste? (Ans - spicy)

This rests on - Does a chilly have a taste? (Ans - yes)

This rests on - Is there something like a chilly? (Ans - yes)

According to me, the entity that remains existent across all of this chain of commonsense component-questions (which are based upon all the assumed knowledge in the original question) is the real KEYWORD. Here it is - TASTE. It is what we are really talking about, in the original question. That's the real "subject" of the matter. When we say - Why does a chilly taste spicy?, what are we talking about REALLY? the Chilly? the Tasting? or the Spiciness? Agreed, there is a sense in which we are talking about each of these (Chilly - we are clearly talking about a chilly; taste - we are talking about tasting; spicy - we are talking about the spiciness), but primarily we are talking about the tasting.

Consider another question - why is this school named Arthur C. Clarke school? Think about this. Even if we are talking about the school, it being named, and the name - 'Arthur C. CLarke school', we are primarily concerned with the naming (of the school as so and so). 

The real keyword in a WHY-question is "verb-centric". The verb is the master!